package com.gaolang.util;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

/**
 　　 * @author dzy
 　　 * 生成验证码图片
 　　 */
public class MakeCertPic {
    //验证码图片中可以出现的字符集，可根据需要修改
    private char mapTable[]={
            'a','b','c','d','e','f',
            'g','h','i','j','k','l',
            'm','n','o','p','q','r',
            's','t','u','v','w','x',
            'y','z','0','1','2','3',
            '4','5','6','7','8','9'};
    /**
     * 功能:生成彩色验证码图片
     * 参数width为生成图片的宽度,参数height为生成图片的高度,参数os为页面的输出流
     */
    public String getCertPic(int width, int height, OutputStream os) {
        if(width<=0)width=60;
        if(height<=0)height=20;
        BufferedImage image = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);
        // 获取图形上下文
        Graphics g = image.getGraphics();
        // 设定背景色
        g.setColor(new Color(0xDCDCDC));
        g.fillRect(0, 0, width, height);
        //画边框
        g.setColor(Color.black);
        g.drawRect(0,0,width-1,height-1);
        // 取随机产生的认证码
        String strEnsure = "";
        // 4代表4位验证码,如果要生成更多位的认证码,则加大数值
        for(int i=0; i<4; ++i) {
            strEnsure+=mapTable[(int)(mapTable.length* Math.random())];
        }
        // 　　将认证码显示到图像中,如果要生成更多位的认证码,增加drawString语句
        g.setColor(Color.black);
        g.setFont(new Font("Atlantic Inline", Font.PLAIN,18));
        String str = strEnsure.substring(0,1);
        g.drawString(str,8,17);
        str = strEnsure.substring(1,2);
        g.drawString(str,20,15);
        str = strEnsure.substring(2,3);
        g.drawString(str,35,18);
        str = strEnsure.substring(3,4);
        g.drawString(str,45,15);
        // 随机产生10个干扰点
        Random rand = new Random();
        for (int i=0;i<10;i++) {
            int x = rand.nextInt(width);
            int y = rand.nextInt(height);
            g.drawOval(x,y,1,1);
        }
        // 释放图形上下文
        g.dispose();
        try {
            // 输出图像到页面
            ImageIO.write(image, "JPEG", os);
        } catch (IOException e) {
            return "";
        }
        return strEnsure;
    }
}